1. Field of the Invention
The invention relates to a motor control device.
2. Description of the Related Art
Some motor control devices are known that are adapted to conduct an electronic throttle control of a vehicle by controlling rotation of a motor (see, e.g., JP-A-2000-18069).
In the motor control devices, a digital control using an inexpensive microcomputer is conducted for the valve opening control of an electronic throttle valve, an analog control is conducted for the current control of the motor provided at a minor loop of the opening control which requires a quick response and a high accuracy, and a variable frequency PWM (pulse width modulation) control is used as the current PWM control.
However, if the variable frequency PWM control is used as the current PWM control, a problem may occur that a variation in drive frequency causes a harsh buzzing noise etc. during the motor drive control.